title: Relevance of biophysical concepts in the scintigraphic detection of gastrointestinal leaks.
abstract: The application of some physical concepts is described to explain the inherent insensitivity of 99Tc(m)-red blood cell (RBC) and 99Tc(m)-human serum albumin (HSA) in the detection of gastrointestinal bleeding and protein-losing enteropathy (PLE), respectively. Inferences drawn from the laws of radioactive decay, partition physics, hydrodynamics and electrostatic forces have been used to suggest that the clearance pattern, size and charge of radiopharmaceuticals, and the viscosity of the medium, affect the sensitivity of these tests. As the outflow from gastrointestinal lesions is non-specific, other labelled macromolecules can be used instead of RBCs or HSA. Based on biophysical concepts, we suggest that chargeless macromolecules in the size range 5-50 nm are superior to the conventional agents used for this purpose.
authors.affiliation: Department of Nuclear Medicine, Institute of Nuclear Medicine and Applied Sciences, Lucknow Marg, Delhi, India.
authors.forename: A
authors.initials: A
authors.lastname: Bhatnagar
authors.forename: T
authors.initials: T
authors.lastname: Srinivasan
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D004912:Erythrocytes; D006471:Gastrointestinal Hemorrhage / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008954:Models, Biological; D011504:Protein-Losing Enteropathies / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012680:Sensitivity and Specificity; D013667:Technetium / Q000493:pharmacokinetics; D013668:Technetium Tc 99m Aggregated Albumin / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D013667:Technetium